High gain monostable fluidic switching device

ABSTRACT

A high gain monostable fluid amplifier serves as a metering valve in which a fluid stream can be deflected from a primary receiver to an alternate receiver by means of control pulses. The frequency and duration of the control pulses provide means for varying the amount of fluid delivered to the alternate receiver. Auxiliary control slots employed in the interaction region provide rapid response to the presence and absence of a control pulse and provide sharp cutoff when switching from the auxiliary receiver to the primary receiver. The control slots are arranged to oppose wall attachment in the primary receiver when a control pulse is present and to assist wall attachment in the primary receiver in the absence of a control pulse. In the preferred form, the metered fluid is liquid and the control fluid is gas, for example, a liquid fuel metered by an air signal.

0 United States Patent 13,586,024

[72] Invent rs J hn-L T018011 3,389,894 6/1968 Binder 261/36 Evanstou;3,467,124 9/1969 Simon 137/815 fi i Primary ExaminerWilliam R. ClineOglesby. Elk Grove lllage. all 01'. Ill.

-' Attorneys-Donald W. Banner, William S. McCurry and John [21] Appl.No. 836,369 w B t h 22 Filed June 25, 1969 c [45] Patented June 22, 1971(73] Assignee Borg-warner Corporation clung! ABSTRACT: A high gainmonostable fluid amplifier serves as a metering valve in which a fluidstream can be deflected from [54] HIGH GAIN MONOSTABLE FLUID: SWTCHING aprimary receiver to an alternate receiver by means of control DEVICEpulses. The frequency and duration of the control pulses pro- 8 Gain, 4Drawing Figs. vide means for varying the amount of fluid deliveredto thealternate receiver. Auxiliary control slots employed in the m- [52]U.S.Cl 137/81-5, teraction region provide rapid response to the presenceand 261/36 absence of a control pulse and provide sharp cutotf when [5l] IIEL Cl witching from the auxiliary receiver to the receiver ofSearch The control 510s are arranged to oppose attachment in 261/36 theprimary receiver when a control pulse is present and to assist wallattachment in the primary receiver in the absence [56] References cuedof a control pulse. 1n the preferred form, the metered fluid is UNlTEDSTATES PATENTS liquid and the control fluid is gas, for example, aliquid fuel 3,386,709 6/ 1968 Drayer 137/815 X metered by an air signal.

PATENIEU JHN22 1911 SHEET 2 [IF 2 ATTORNEY IHIIGII GAIN MONOSTABLEFLUIDIC SWITCHING DEVICE SUMMARY OF THE INVENTION The present inventionrelates generally to fluid logic elements and more particularly to adigital-type amplifier.

Fluid amplifier devices, in general, have the capability of selectivelydeflecting a fluid stream among alternate receivers, in response to theapplication of fluid pressure signals. It is an object of the presentinvention to provide a fluid amplifier for metering the fluid deliveredto a selected receiver in accordance with a fluid pressure controlsignal. A further object is to provide a fluid amplifier whichsubstantially excludes flow to a selected receiver in the absence of acontrol signal. A further object of the invention is to provide a fluidamplifier in which the behavior of the fluid stream is closelycontrolled by the fluid pressure control signal which may be applied inthe form of pulses of varying duration or frequency. A still furtherobject is to provide a fluid amplifier in which a relatively high energyfluid stream such as a liquid can be controlled by a relatively lowenergy control signal such as air. A still further object is to providea fluid amplifier for metering a fluid stream to alternate receivers inwhich the receivers are subjected to substantially different pressureconditions. An additional object is to provide a fluid amplifier formetering liquid fuel delivered to a negative pressure region, such asthe intake system of an internal combustion engine, by means of acontrol signal such as air pulses corresponding to the speed and load ofthe engine. Other objects and advantages of the invention will becomeapparent from the following description together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an amplifieraccording to the present invention, with portions removed to reveal theinternal passages therein;

FIG. 2 is a fragmentary section view taken along the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary section view taken along the line 3-3 of FIG. I;and

FIG. 4 is a plan view similar to FIG. 1, of an alternate embodiment ofthe fluid amplifier of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in more detail tothe drawings and particularly FIGS. 1, 2 and 3 thereof, the referencecharacter generally indicates a fluid switching device according to thepresent invention. The body of switching device 10 may include a stackof plates 11, 12, 13 of a fluid impervious material such as plastic, inwhich the various fluid passages described hereinafter are formed. Theplates are secured to each other as by cap screws 15 to form a fluidimpervious body.

A fluid interaction chamber 14 is defined in part by walls l6, 17 inplate 12 and by the inner surfaces 18, 19 of plates 11 and 13. A firstreceiver duct 21 extends from interaction chamber 14 sharing the commonwall 16 and having the spaced wall 22. First receiver duct 21 terminatesin the first outlet port 23. A second receiver duct 24 is defined inpart by the wall portions 26, 27, 28 and extends from the interactionchamber 14 to the second outlet port 29.

A control chamber 31 is formed in plate 12 and communicates withinteraction chamber 14 by means of a control nozzle 32 extendingtransversely through wall 16. A supply chamber 33 includes a powernozzle 34 extending substantially parallel to wall 16 and opening intointeraction chamber 14 opposite first receiver duct 21. An ambientchamber 36 and nozzle 37 are arranged oppositely to control chamber 31and nozzle 32 and communicate with interaction chamber 14 through wallportion 17 A group of control slots 38, here shown as four in number,open through wall 16 into interaction chamber 14 at an angle withrespect to power jet 34. Control slots 38 act as auxiliary controlnozzles aiding in switching flow between receivers 21 and 24. Anauxiliary control channel 39 is defined in part by wall portions 41, 42and communicates with control slots 38. Auxiliary control channel 39also communicates with control chamber 31, with first outlet port 23 andwith the common attachment wall 16. For convenience, auxiliary channel39 is here shown as a single continuous slot formed in bottom plate 1 I,however, the channel may be formed in plate 12 if desired, or a pair ofchannels may be formed in plates 11 and 13 if desired. Auxiliary channel39 need not be a single continuous passage, but may be in the form ofseparate channels communicating control slots 38 with other portions ofthe device.

When amplifier 10 is used for metering, fluid is diverted into receiver24 for a given time interval, it is therefore important that fluid beexcluded from receiver 24 at the end of the time interval which ismeasured in'terms of duration of the control pulse in chamber 31. Theamplifier is geometrically biased to switch fluid back to first receiver21 in the absence of a control pulse. In order to achieve sharp cutoffwhen switching the fluid stream from receiver 24 back to the firstreceiver 21, it is important that one of the auxiliary slots 38 beconnected to a downstream portion of receiver 21. When the control pulseis terminated, fluid returns to receiver 21, and the flow of fluid inreceiver 21 tends to purge or scavenge the control slot resulting inevacuation along the attachment wall in the interaction chamber. Thisevacuation of the attachment wall supplements the return of the fluidstream to first receiver 21.

While not essential to the metering function, it is neverthelessdesirable to switch the fluid stream quickly into receiver 24 when acontrol pulse is initiated. It is therefore desirable that at least oneof the control slots 38 be connected to the control chamber 31. Thuswhen a control pulse is initiated in control chamber 31, control jetsissue from control nozzle 32 and from the connected control slot 38which then functions as a supplementary or auxiliary control nozzle. Thesupplementary jet issuing from the control slot 38 provides a bubble orwedge of air along the attachment wall 16 which spoils the wallattachment of the liquid jet issuing from power nozzle 34. At the sametime, the control jet issuing from control nozzle 32 interacts with theliquid jet issuing from power nozzle 34 switching the liquid stream intoreceiver 24.

As shown in the drawing the control slots 38 are connected to both thedownstream portion of receiver 21 and to the control chamber 31, thusthe control slots participate both in switching the stream into receiver24 when a control pulse is initiated and in excluding the stream fromreceiver 24 when the control pulse is terminated. The comprehensiveconfiguration shown in the drawing may be modified if desired, in orderto provide a particular level of performance. For example, single ormultiple control slots may be employed depending upon the energy levelof the jet issuing from power nozzle 34in proportion to the energy levelof the control pulse. In other configurations, it may be desirable toconnect one or more control slots to a downstream portion of receiver 21without at the same time being connected to the control chamber 31, orsome of the control slots may be connected downstream of receiver 21while others are connected with control chamber 31. The number of slotsemployed and their connections to other portions of the device providemeans for selecting desired switching characteristics of the device.

A circuit employing the switching device 10 is shown schematically inFIG. 1. A pulse generating apparatus 43 is connected to control chamber31 by means of a conduit 44. Pulse generating apparatus 43 may take manyforms depending upon the metering function to be performed by theamplifier 10. In its simplest form pulsing apparatus 43 can be a simpleOFF ON valve for regulating a fluid control pressure applied to controlchamber 31. On the other hand, pulsing apparatus 43 may involve morecomplex apparatus for supplying a control signal in which the frequencyand/or the duration of the fluid pressure pulses are regulated inaccordance with a selected condition or combination of conditions.

Supply chamber 33 is connected to a conduit 46 and pump 47 for supplyingfluid under pressure to the switching device 10. First outlet port 23 isconnected to a conduit 43 arranged to deliver fluid to the sump 49.Second outlet port 29 is connected to a conduit 51 for delivering fluidto an alternate receptacle 53. Ambient chamber 36 is vented toatmosphere by means of conduit 45. If desired, ambient chamber 36 may beconnected to an adjustable source of fluid pressure for adjusting theswitching bias of amplifier 10.

Considering now the operation of switching device as shown in FIG. 1,fluid such as a liquid is supplied under pressure to supply chamber 33.Nozzle 34 projects a stream of fluid through interaction chamber 14 intofirst receiver duct 21 from which the fluid is conducted to sump 49 bymeans of first outlet port 23 and conduit 43. In the absence of a fluidcontrol pressure in control chamber 31, the fluid stream from powernozzle 34 is directed toward first receiver duct 21. Movement of fluidin first receiver duct 21 tends to evacuate auxiliary channel 39 whichin turn tends to evacuate control slots 38. Also, discharge of fluidthrough first outlet port 23 tends to evacuate auxiliary channel 39 andcontrol slots 38 in the absence of a control fluid pressure in controlchamber 31. Evacuation of control slots 38 tend to enhance wallattachment of the fluid stream to the wall 16 thus substantiallyexcluding the fluid stream from second receiver duct 24. Thus, in theabsence of a control signal, the fluid is recirculated to sump 49.

DESCRllPTlON OF AN ALTERNATE EMBODIMENT Referring now to FIG. 4, analternate embodiment of the fluidic switching device of the presentinvention is shown, particularly adapted for use as a fuel meteringdevice for an internal combustion engine.

The metering valve 110 is similar in many respects to the constructionshown in FIG. 1, but having modifications in the second receiver duct.Metering valve 1111 includes an interaction chamber 114, a firstreceiver duct 121, a first outlet port 123, a control chamber 131,control nozzle 132, supply chamber 133, power nozzle 134, ambientchamber 136, ambient nozzle 137, control slots 138 and auxiliary controlchannel 139. The above named portions of the device may be similar inconstruction and function to those described in connection with FIG. 1,to which reference should be made for a more detailed description.

Referring now to the modified second receiver duct 124, the wallportions 126, 128 converge toward each other forming a fluid restrictionas indicated at 127.

The spaced walls of second receiver duct 124 then diverge from eachother as indicated by portions 156, 157, encompassing a pair oflaterally spaced vent ports 159, The walls then reconverge toward eachother as indicated by portions 161, 162 to form a second fluidrestriction 163. The sidewall portions 156, 157, 161, 162 together withtop and bottom plates (such as plates 11 and 13 of FIG. 1) form a ventchamber or isolation chamber 164 in second receiver duct 124 betweeninteraction chamber 114 and second outlet port 129.

Referring now to the schematic circuit diagram shown in connection withmetering valve 110, a fuel tank 149 and fuel pump 147 supply liquid fuelto supply chamber 133 by means of conduit 146. In the absence of acontrol signal, the fuel is recirculated back to tank 149 by means offirst receiver duct 121, first outlet port 123 and return conduit 148.Interaction chamber 114 is vented to atmosphere or to a bias control byambient chamber 136, nozzle 137 and conduit 145. Pulse generator 143preferably provides a series of air pressure pulses in which thefrequency of the pulses is a function of engine speed and the durationof a pulse is a function of engine load. This signal is conducted tocontrol chamber 131 by means of conduit 144 and serves to deflect fuelissuing from power nozzle 134 into second receiver duct 124.

Second outlet port 129 is adapted for incorporation into the intakesystem of an internal combustion engine where it is subjected tonegative pressures ranging from a few inches of water to several inchesof mercury. The vent chamber 164 provides means for isolating suchnegative pressure conditions from the control pressure and biasing meansacting in the interaction chamber.

in the absence of a control pressure, no flow occurs in second receiver124. In this case negative pressure in second outlet port 129 results inthe bleeding of air from vent ports 158, 159 and conduits 166, 167through vent chamber 164 and second restriction 163 into the secondoutlet port while the first restriction 127 serves to isolateinteraction chamber 114 from vent chamber 164. Thus in the absence of acontrol signal, fuel is returned through first receiver 121 even thoughsecond outlet port 129 is subjected to a high negative pressure.

When a control pressure signal is present, fuel is deflected into secondreceiver duct 124 issuing as a stream through restriction 127 into ventchamber 164. The converging wall portions 161, 162 of vent chamber 164together with the negative pressure in second outlet port 129 incooperation with the vent ports 158, 159 result in reformation of thefluid stream which then projects as a stream through restriction 163.The fluid stream thus projected into second outlet port 129 becomesdispersed in the intake air system for the internal combustion engine.

The foregoing description is directed to particular embodiments of thedevice which are capable of switching a liquid stream typical ofinternal combustion engine fuel by means of an air signal. Thedescription is therefore exemplary of a preferred embodiment of thedevice for use with fluids of a particular density under a particularset of pressure conditions. Appropriate modifications will be suggestedto those skilled in the art in view of the pressures and densities ofthe operating fluids with which the device is to be used.

What we claim is:

1. A fluid amplifier device capable of controlling a liquid jet by meansof a gas control pulse, comprising a body member having defined thereina fluid interaction chamber, first and second receiver ductscommunicating with said interaction chamber, a power nozzlecommunicating with said interaction chamber and aligned with said firstreceiver duct adapted to project a liquid jet through said interactionchamber, a first control nozzle angularly disposed with respect to saidpower nozzle opening into said interaction chamber adapted to project agas jet into said interaction chamber, and auxiliary control meansincluding at least one auxiliary control nozzle opening into saidinteraction chamber spaced downstream from said first control nozzle,and an auxiliary channel communicating said auxiliary control nozzlewith a downstream portion of said first receiver duct.

2. A fluid amplifier according to claim 1, wherein said auxiliarychannel communicates said auxiliary control nozzle with said firstcontrol nozzle and with said downstream portion of said first receiverduct.

3. A fluid amplifier according to claim 1, in which said interactionchamber and said first receiver duct have a common wall member, saidfirst control nozzle and said auxiliary control nozzle opening throughsaid common wall member into said interaction chamber, said auxiliarycontrol nozzle also communicating with a portion of said wall memberlocated in said first receiver duct.

4. A fluid amplifier according to claim 3, wherein said auxiliarychannel extends along a portion of said common wall member in saidinteraction chamber and said first receiver duct, providingcommunication between said auxiliary control nozzle and said downstreamportion of said first receiver duct.

5. A fluid amplifier according to claim 3, including a plurality ofauxiliary control nozzles opening through said common wall member intosaid interaction chamber.

6. A fluid amplifier according to claim 5, including a control chamberconnected to said first control nozzle, and an auxiliary channelconnected to said control chamber and extending along a portion of saidcommon wall member communicating said plurality of auxiliary controlnozzles with said control chamber and with a downstream portion of saidfirst receiver duct.

7. A fluid amplifier device including an interaction chamber, a powernozzle opening into said interaction chamber, and first and secondreceiver ducts extending from said interaction chamber, said interactionchamber having biasing means associated therewith for normally directingfluid flow from said power nozzle into said first receiver duct, andhaving pressure control means associated therewith for selectivelyswitching fluid flow into said second receiver duct, said secondreceiver duct being connected to an outlet port adapted for connectionto a negative pressure region, said second receiver duct including apair of spaced sidewall portions converging toward each other defining afirst fluid restrictor, said sidewall portions diverging from each otherdefining an isolation chamber and reconverging toward each otherdefining a second fluid restrictor disposed between said interactionchamber and said outlet port, isolating said negative pressure regionfrom said biasing means and control means, said second fluid restrictorbeing in substantial alignment with said first fluid restrictor, saidisolation chamber including a pair of laterally spaced venting portsdisposed on opposite sides of a line extending through said first andsecond restrictors.

8. A fluid amplifier according to claim 7, adapted for selectivelydelivering a measured charge of liquid fuel into said second receiverduct, said outlet port forming a portion of an air induction passage foran internal combustion engine, said isolation chamber including a pairof converging sidewall portions defining an outlet nozzle opening intosaid outlet port, said isolation chamber including a pair of laterallyspaced venting ports arranged on opposite sides of said outlet nozzle,said venting ports and outlet nozzle providing means for pro jectingsaid charge of liquid fuel into said air induction passage for dispersalinto an air stream.

1. A fluid amplifier device capable of controlling a liquid jet by meansof a gas control pulse, comprising a body member having defined thereina fluid interaction chamber, first and second receiver ductscommunicating with said interaCtion chamber, a power nozzlecommunicating with said interaction chamber and aligned with said firstreceiver duct adapted to project a liquid jet through said interactionchamber, a first control nozzle angularly disposed with respect to saidpower nozzle opening into said interaction chamber adapted to project agas jet into said interaction chamber, and auxiliary control meansincluding at least one auxiliary control nozzle opening into saidinteraction chamber spaced downstream from said first control nozzle,and an auxiliary channel communicating said auxiliary control nozzlewith a downstream portion of said first receiver duct.
 2. A fluidamplifier according to claim 1, wherein said auxiliary channelcommunicates said auxiliary control nozzle with said first controlnozzle and with said downstream portion of said first receiver duct. 3.A fluid amplifier according to claim 1, in which said interactionchamber and said first receiver duct have a common wall member, saidfirst control nozzle and said auxiliary control nozzle opening throughsaid common wall member into said interaction chamber, said auxiliarycontrol nozzle also communicating with a portion of said wall memberlocated in said first receiver duct.
 4. A fluid amplifier according toclaim 3, wherein said auxiliary channel extends along a portion of saidcommon wall member in said interaction chamber and said first receiverduct, providing communication between said auxiliary control nozzle andsaid downstream portion of said first receiver duct.
 5. A fluidamplifier according to claim 3, including a plurality of auxiliarycontrol nozzles opening through said common wall member into saidinteraction chamber.
 6. A fluid amplifier according to claim 5,including a control chamber connected to said first control nozzle, andan auxiliary channel connected to said control chamber and extendingalong a portion of said common wall member communicating said pluralityof auxiliary control nozzles with said control chamber and with adownstream portion of said first receiver duct.
 7. A fluid amplifierdevice including an interaction chamber, a power nozzle opening intosaid interaction chamber, and first and second receiver ducts extendingfrom said interaction chamber, said interaction chamber having biasingmeans associated therewith for normally directing fluid flow from saidpower nozzle into said first receiver duct, and having pressure controlmeans associated therewith for selectively switching fluid flow intosaid second receiver duct, said second receiver duct being connected toan outlet port adapted for connection to a negative pressure region,said second receiver duct including a pair of spaced sidewall portionsconverging toward each other defining a first fluid restrictor, saidsidewall portions diverging from each other defining an isolationchamber and reconverging toward each other defining a second fluidrestrictor disposed between said interaction chamber and said outletport, isolating said negative pressure region from said biasing meansand control means, said second fluid restrictor being in substantialalignment with said first fluid restrictor, said isolation chamberincluding a pair of laterally spaced venting ports disposed on oppositesides of a line extending through said first and second restrictors. 8.A fluid amplifier according to claim 7, adapted for selectivelydelivering a measured charge of liquid fuel into said second receiverduct, said outlet port forming a portion of an air induction passage foran internal combustion engine, said isolation chamber including a pairof converging sidewall portions defining an outlet nozzle opening intosaid outlet port, said isolation chamber including a pair of laterallyspaced venting ports arranged on opposite sides of said outlet nozzle,said venting ports and outlet nozzle providing means for projecting saidcharge of liquid fuel into said air induction passage for dispersal intoan air stream.